This invention relates to a swash-plate compressor and, in particular, to a connection mechanism between a piston and a swash plate which are included in the swash-plate compressor.
Generally, a swash-plate compressor comprises a drive shaft, a swash plate coupled to the drive shaft, and a plurality of pistons operatively coupled to the swash plate. When the drive shaft is rotated by a drive unit in the manner known in the art, the swash plate has a motion which in turn causes a reciprocating motion of each piston within a cylinder bore. Broadly, the swash-plate compressor includes two different types which will hereafter be described as first and second conventional swash-plate compressors.
The first conventional swash-plate compressor is described, for example, in Japanese Patent Publication (JP-B) No. 61627/1990 and has a structure in which the swash plate is fixedly and integrally supported on the drive shaft so as to rotate together with the drive shaft. In other words, the swash plate is unrotatable relative to the drive shaft. The swash plate is slidably coupled to the pistons in an axial direction of the drive shaft. During operation of the first conventional swash-plate compressor, the pistons simply perform the reciprocating motion while the swash plate is rotated together with the drive shaft. This causes a high-speed sliding motion between each piston and the swash plate. It is therefore required to take a fully effective countermeasure against the above-mentioned high-speed sliding motion.
On the other hand, the second conventional swash-plate compressor has a structure in which the swash plate is coupled to the drive shaft so as to perform the swinging motion alone without being rotated together with the drive shaft. In other words, the swash plate is rotatable relative to the drive shaft. When the drive shaft is rotated by the drive unit, the swash plate has a swinging motion which is then converted into the reciprocating motion of each piston.
In the second conventional swash-plate compressor which will later be described in detail in conjunction with the drawing, the swash plate is connected to each piston via a piston rod. Therefore, a rotation stopper mechanism is essential for stopping a rotation of the swash plate as is well known in the art, so that the compressor is complicated in structure. In addition, it is difficult to arrange the rotation stopper mechanism concentrically with the drive shaft. Generally, the rotation stopper mechanism is arranged at a particular position in the vicinity of the periphery of the swash plate. With this structure, the swinging motion of the swash plate inevitably becomes nonuniform or unbalanced. Specifically, loci of the swinging motion are different at those points which are equally spaced from the center of the swinging motion but are near to and apart from the rotation stopper mechanism. This may result in occurrence of vibration and noise.